The present invention relates generally to manure spreaders and, more particularly, to a drive system for providing rotational power to the moving components of a manure spreader, namely, the apron assembly and the widespread discharge means commonly referred to as the beater assembly.
Manure spreaders heretofore manufactured utilize a finitely variable drive system to transfer power to the rotatable components. One type of drive system is described in U.S. Pat. No. 3,722,306 granted to W. R. Campbell et al. and in U.S. Pat. No. 3,722,307 granted to W. R. Campbell, both of which issued Mar. 27, 1973. Typical of such spreaders, rotational power is delivered rearwardly from the tractor, from which the manure spreader trails, via a power input shaft.
A pulley attached to the power input shaft transfers the rotational power to a second pulley by means of a drive belt interconnecting the two pulleys. The second pulley is attached to a drive shaft running along the outside of the spreader. This drive shaft runs directly into a gearbox driving the beater assembly. The apron assembly is driven off this rotating drive shaft through a transmission mechanism and jaw clutch which is finitely variable via a control linkage extending to the front of the machine.
Another known drive system for a manure spreader is commonly referred to as a ratchet drive. An example of this ratchet drive system can be found in U.S. Pat. No. 2,699,337 granted to A. M. Best on Jan. 11, 1955. The speed of the apron assembly is finitely adjustable according to the number of notches (or ratchet teeth) the coacting pawl is allowed to engage in one stroke of the pitman arm.
These drives have been found to be difficult to shift while operating under loaded conditions. When shifting is accomplished, shock loads are imposed on the drive line. Also, the finitely adjustable apron seeds may not be optimum for certain operating conditions. Moreover, finite adjustments are usually accomplished through a mechanical linkage mechanism which requires frequent maintenance and is susceptible to being easily damaged.
In addition, most present day manure spreaders require cycling the drive system completely through to the cleanout position before returning to the neutral position. Another disadvantage to manure spreaders with beater drive jaw clutches is that the operator is required to remember to disengage the tractor's power takeoff before going into the neutral position in order to prevent damage to the jaw clutch.
Other types of manure spreader drive systems are described in U.S. Pat. Nos. 3,156,124 and in 3,448,930. The former reference reveals a drive system which is also only finitely adjustable among predetermined speeds, while the latter reference exemplifies a ground driven drive system.